Employee and Retiree Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2014

Employee and Retiree Benefit Plans [Abstract]

Components of Net Periodic Benefit Expense

	Three Months Ended September 30,
	Pension Benefits				Other Postretirement Benefits
(Thousands of dollars)		2014		2013	2014		2013
Service cost	$	6,208		7,252		672		1,232
Interest cost		8,239		8,450		1,278		1,352
Expected return on plan assets		(8,506)		(8,257)		–		–
Amortization of prior service cost		227		262		(20)		(35)
Amortization of transitional asset		208		125		1		2
Recognized actuarial loss		1,735		4,591		59		391
Special termination benefits		–		849		–		–
Curtailments		–		1,366		–		(443)
Net periodic benefit expense	$	8,111		14,638		1,990		2,499
	Nine Months Ended September 30,
	Pension Benefits				Other Postretirement Benefits
(Thousands of dollars)	2014		2013		2014		2013
Service cost	$	19,048		21,949		2,016		3,629
Interest cost		24,707		22,581		3,833		3,865
Expected return on plan assets		(25,514)		(21,526)		–		–
Amortization of prior service cost		680		841		(61)		(121)
Amortization of transitional asset		628		366		4		6
Recognized actuarial loss		5,201		12,882		177		1,321
Special termination benefits		–		849		–		–
Curtailments		–		1,366		–		(443)
Net periodic benefit expense	$	24,750		39,308		5,969		8,257